First things first: is this list active or is there a better tool for
asking how to build PDT ?

The actual problem:

I've been given the task to update an eclipse plugin for work. This
consists mainly of a small patchset against an old version of PDT (its
not even a patchset, just hacked in an compiled - deployed)

I tried:

1 cloning PDT master, importing the projects
2 fetching all deps (DTLK, equinox, xsd, apache ant,...) I came across
3 figure out how to work with eclipse
4 even installed a so called delta-package
5 workarounded (rm *.RSA) a 2-time jarsign bug in eclipse 4.3.1 which
happend on org.apache.ant

and now have:
an eclipse workspace where I have 50 or so plugins which I then can
export via Product export "phpide"

and I am wondering - isn't there an easier way to git clone the 3 or so
subprojects of PDT I actually need and
then somehow compile them in a fashion where I can put them into, say
dropins.
It would be best if one could use the standard PDT eclipse and dropin
the 3 custom jars to get the custom functionality. Or something equally
easy.